TRIB2 confers resistance to anti-cancer therapy by activating the serine/threonine protein kinase AKT

Association of WHSC1/NSD2 and T-cell infiltration with prostate cancer metastasis and prognosis

Progress in immunotherapy for prostate cancer (PCa) lags that for other cancers, mainly because of limited immune infiltration in PCa. This study aimed to assess the feasibility of NSD2 as an immunotherapeutic target in PCa. Immunohistochemistry was performed to evaluate the expression pattern of NSD2 in 34 cases of benign prostatic hyperplasia (BPH), 36 cases of prostatic intraepithelial neoplasia (PIN), and 57 cases of PCa, including 19 cases of metastatic castration-resistant prostatic cancer (mCRPC). Single-cell RNA sequencing and gene set enrichment analysis (GSEA) were used to correlate NSD2 with certain downstream pathways. Furthermore, the Immuno-Oncology-Biological-Research (IOBR) software package was used to analyze the potential roles of NSD2 in the tumor microenvironment. We found that the positive expression rate of NSD2 increased progressively in BPH, PIN and PCa. mCRPC had the highest staining intensity for NSD2. High NSD2 expression was positively correlated with the infiltration level of CD4+ tumor-infiltrating lymphocytes (TILs) and negatively correlated with that of CD8+ TILs. Importantly, a new immune classification based on NSD2 expression and CD4+ TILs and CD8+ TILs was successfully used to stratify PCa patients based on OS.PSA and CD4+ TILs are independent risk factors for PCa bone metastasis. This study demonstrates a novel role for NSD2 in defining immune infiltrate on in PCa and highlights the great potential for its application in immunotherapy response evaluation for prostate malignancies.

FUS-dependent microRNA deregulations identify TRIB2 as a druggable target for ALS motor neurons

MicroRNAs (miRNAs) modulate mRNA expression, and their deregulation contributes to various diseases including amyotrophic lateral sclerosis (ALS). As fused in sarcoma (FUS) is a causal gene for ALS and regulates biogenesis of miRNAs, we systematically analyzed the miRNA repertoires in spinal cords and hippocampi from ALS-FUS mice to understand how FUS-dependent miRNA deregulation contributes to ALS. miRNA profiling identified differentially expressed miRNAs between different central nervous system (CNS) regions as well as disease states. Among the up-regulated miRNAs, miR-1197 targets the pro-survival pseudokinase Trib2. A reduced TRIB2 expression was observed in iPSC-derived motor neurons from ALS patients. Pharmacological stabilization of TRIB2 protein with a clinically approved cancer drug rescues the survival of iPSC-derived human motor neurons, including those from a sporadic ALS patient. Collectively, our data indicate that miRNA profiling can be used to probe the molecular mechanisms underlying selective vulnerability, and TRIB2 is a potential therapeutic target for ALS.

TRIB1 confers therapeutic resistance in GBM cells by activating the ERK and Akt pathways

GBM (Glioblastoma) is the most lethal CNS (Central nervous system) tumor in adults, which inevitably develops resistance to standard treatments leading to recurrence and mortality. TRIB1 is a serine/threonine pseudokinase which functions as a scaffold platform that initiates degradation of its substrates like C/EBPα through the ubiquitin proteasome system and also activates MEK and Akt signaling. We found that increased TRIB1 gene expression associated with worse overall survival of GBM patients across multiple cohorts. Importantly, overexpression of TRIB1 decreased RT/TMZ (radiation therapy/temozolomide)-induced apoptosis in patient derived GBM cell lines in vitro. TRIB1 directly bound to MEK and Akt and increased ERK and Akt phosphorylation/activation. We also found that TRIB1 protein expression was maximal during G2/M transition of cell cycle in GBM cells. Furthermore, TRIB1 bound directly to HDAC1 and p53. Importantly, mice bearing TRIB1 overexpressing tumors had worse overall survival. Collectively, these data suggest that TRIB1 induces resistance of GBM cells to RT/TMZ treatments by activating the cell proliferation and survival pathways thus providing an opportunity for developing new targeted therapeutics.

The 'omics of obesity in B-cell acute lymphoblastic leukemia

The obesity pandemic currently affects more than 70 million Americans and more than 650 million individuals worldwide. In addition to increasing susceptibility to pathogenic infections (eg, SARS-CoV-2), obesity promotes the development of many cancer subtypes and increases mortality rates in most cases. We and others have demonstrated that, in the context of B-cell acute lymphoblastic leukemia (B-ALL), adipocytes promote multidrug chemoresistance. Furthermore, others have demonstrated that B-ALL cells exposed to the adipocyte secretome alter their metabolic states to circumvent chemotherapy-mediated cytotoxicity. To better understand how adipocytes impact the function of human B-ALL cells, we used a multi-omic RNA-sequencing (single-cell and bulk transcriptomic) and mass spectroscopy (metabolomic and proteomic) approaches to define adipocyte-induced changes in normal and malignant B cells. These analyses revealed that the adipocyte secretome directly modulates programs in human B-ALL cells associated with metabolism, protection from oxidative stress, increased survival, B-cell development, and drivers of chemoresistance. Single-cell RNA sequencing analysis of mice on low- and high-fat diets revealed that obesity suppresses an immunologically active B-cell subpopulation and that the loss of this transcriptomic signature in patients with B-ALL is associated with poor survival outcomes. Analyses of sera and plasma samples from healthy donors and those with B-ALL revealed that obesity is associated with higher circulating levels of immunoglobulin-associated proteins, which support observations in obese mice of altered immunological homeostasis. In all, our multi-omics approach increases our understanding of pathways that may promote chemoresistance in human B-ALL and highlight a novel B-cell-specific signature in patients associated with survival outcomes.

TRIB2 safeguards naive T cell homeostasis during aging

Naive CD4+ T cells are more resistant to age-related loss than naive CD8+ T cells, suggesting mechanisms that preferentially protect naive CD4+ T cells during aging. Here, we show that TRIB2 is more abundant in naive CD4+ than CD8+ T cells and counteracts quiescence exit by suppressing AKT activation. TRIB2 deficiency increases AKT activity and accelerates proliferation and differentiation in response to interleukin-7 (IL-7) in humans and during lymphopenia in mice. TRIB2 transcription is controlled by the lineage-determining transcription factors ThPOK and RUNX3. Ablation of Zbtb7b (encoding ThPOK) and Cbfb (obligatory RUNT cofactor) attenuates the difference in lymphopenia-induced proliferation between naive CD4+ and CD8+ cells. In older adults, ThPOK and TRIB2 expression wanes in naive CD4+ T cells, causing loss of naivety. These findings assign TRIB2 a key role in regulating T cell homeostasis and provide a model to explain the lesser resilience of CD8+ T cells to undergo changes with age.

Effect of COP1 in Promoting the Tumorigenesis of Gastric Cancer by Down-Regulation of CDH18 via PI3K/AKT Signal Pathway

In recent years, the involvement of E3 ubiquitin ligase constitutive photomorphogenesis 1 (COP1) in the tumorigenesis of gastric cancer (GC) has been elucidated. However, the exact underlying mechanism remains to be clarified. In the present study, the expression profiles of COP1 in GC were derived from the Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA) databases, followed by verification via immunohistochemical staining (IHC), Western blotting (WB), and quantitative real-time polymerase chain reaction (qRT-PCR) reaction assays on clinical samples. In vitro, the gain- and loss-of-function experiments of COP1 protein were conducted to explore its role in GC cell lines HGC-27 and SGC-7901. Furthermore, we screened the interaction protein of COP1 by yeast two-hybrid experiment and verified their combination by co-immunoprecipitation (co-IP). We preliminary explored the possible underlying mechanisms of COP1 protein in GC cell lines via WB. COP1 was upregulated in GC tissues compared with the corresponding non-carcinoma tissues. In vitro, the upregulation of COP1 protein promoted the proliferation and migration of GC cells. The yeast two-hybrid experiment and co-IP indicated that Cadherin 18 (CDH18) could constitute a complex with COP1. Moreover, cells with COP1 over-expression showed low levels of CDH18 expression, with the intracellular PI3K/AKT pathway activated and the malignancy of GC cell lines enhanced. Our findings demonstrated that COP1 promoted the GC tumorigenesis by downregulated CDH18 with the involvement of PI3K/AKT signaling pathway in cell lines, suggesting the potential of COP1 as a prognostic biomarker and therapeutic target for GC.

FoxO3 Regulates the Progress and Development of Aging and Aging-Related Diseases

Aging is an inevitable risk factor for many diseases, including cardiovascular diseases, neurodegenerative diseases, cancer, and diabetes. Investigation into the molecular mechanisms involved in aging and longevity will benefit the treatment of age-dependent diseases and the development of preventative medicine for agingrelated diseases. Current evidence has revealed that FoxO3, encoding the transcription factor (FoxO)3, a key transcription factor that integrates different stimuli in the intrinsic and extrinsic pathways and is involved in cell differentiation, protein homeostasis, stress resistance and stem cell status, plays a regulatory role in longevity and in age-related diseases. However, the precise mechanisms by which the FoxO3 transcription factor modulates aging and promotes longevity have been unclear until now. Here, we provide a brief overview of the mechanisms by which FoxO3 mediates signaling in pathways involved in aging and aging-related diseases, as well as the current knowledge on the role of the FoxO3 transcription factor in the human lifespan and its clinical prospects. Ultimately, we conclude that FoxO3 signaling pathways, including upstream and downstream molecules, may be underlying therapeutic targets in aging and age-related diseases.

Convallatoxin Inhibits Cell Proliferation and Induces Cell Apoptosis by Attenuating the Akt-E2F1 Signaling Pathway in K562 Cells

Objective: To determine the effect of convallatoxin on K562 cell proliferation and apoptosis. Methods: CCK-8 assay was used to detect cell proliferation; PI staining, JC-1 staining, and Annexin V-FITC/PI double staining were used to analyze the cell cycle, cell mitochondrial membrane potential, and cell apoptosis; and Western blotting was used to detect cleaved caspase-9, cleaved caspase-3, Bcl-2, Bax, and E2F1 expression and Akt phosphorylation. Subsequently, AutoDock software was used to determine the interaction between convallatoxin and Akt1. Results: Upon treatment with convallatoxin, the proliferation of K562 cells was inhibited, the cells were arrested at the S and G2/M phases, and cell apoptosis was significantly induced. In addition, Akt phosphorylation and E2F1 expression were significantly decreased, whereas E2F1 overexpression rescued convallatoxin-induced cell proliferation and apoptosis. In addition, a molecular docking assay indicated that convallatoxin could bind to Akt1. Conclusion: Convallatoxin inhibited cell proliferation and induced mitochondrial-related apoptosis in K562 cells by reducing the Akt-E2F1 signaling pathway, indicating that it is a potential agent for treating leukemia.

MDFI is a novel biomarker for poor prognosis in LUAD

Background

Approximately 80% of lung cancers are non-small cell lung cancers (NSCLC). Lung adenocarcinoma (LUAD) is the main subtype of NSCLC. The incidence and mortality of lung cancer are also increasing yearly. Myogenic differentiation family inhibitor (MDFI) as a transcription factor, its role in lung cancer has not yet been clarified.

Methods

LUAD data were downloaded from The Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO), analyzed and plotted using the R language. Associations between Clinical information and MDFI expression were assessed using logistic regression analyses to explore the effects of MDFI on LUAD. Two sets of tissue microarrays (TMAs) further confirmed the overexpression of MDFI in LUAD and its impact on prognosis. In addition, we examined the correlation between MDFI and immune infiltration. To investigate the effect of MDFI on the biological behavior of LUAD tumor cells by GSEA and GO/KEGG analysis. The survival status and somatic mutational characteristics of patients according to MDFI levels were depicted and analyzed.

Results

Expression of high MDFI in LUAD tissues via analyzing TCGA dataset (P <0.001). Kaplan-Meier survival analysis indicated a poor prognosis for those patients with LUAD who had upregulated MDFI expression levels (P <0.001). This was also verified by two groups of TMAs (P=0.024). Using logistic statistics analysis, MDFI was identified as an independent predictive factor and was associated with poor prognosis in LUAD (P <0.001, P =0.021). Assessment of clinical characteristics, tumor mutation burden (TMB), and tumor microenvironment (TME) between high- and low-expression score groups showed lower TMB, richer immune cell infiltration, and better prognosis in the low-risk group.

Conclusion

This study showed that MDFI was overexpressed in LUAD and was significantly associated with poor prognosis, indicating that MDFI may be used as a potential novel biomarker for the diagnosis and prognosis of LUAD. MDFI is associated with immune infiltration of LUAD and it is reasonable to speculate that it plays an important role in tumor proliferation and spread. In view of the significant differences in MDFI expression between different biological activities, LUAD patients with MDFI overexpression may obtain more precise treatment strategies in the clinic.

A novel 7 RNA-based signature for prediction of prognosis and therapeutic responses of wild-type BRAF cutaneous melanoma

Background

The prognosis of wild-type BRAF cutaneous melanoma (WT Bf-CM) patients remains poor due to the lack of therapeutic options. However, few studies have investigated the factors contributing to the prognosis of WT Bf-CM patients.

Methods

In this paper, we proposed and validated a novel 7-RNA based signature to predict the prognosis of WT Bf-CM by analyzing the information from TCGA database.

Results

Dependence of this signature to other clinical factors were verified and a nomogram was also drawn to promote its application in clinical practice. Functional analysis suggested that the predictive function of this signature might attribute to the prediction of the up-regulation of RNA splicing, transcription, and cellular proliferation in the high-risk group, which have been demonstrated to be linked to malignancy of cancer. Moreover, functional analysis and therapy response analysis supported that the prognosis is highly related to PI3K/Akt/mTOR pathway among WT Bf-CM patients.

Conclusion

Collectively, this study will provide a preliminary bioinformatics evidence for the molecular mechanism and potential drug targets that could improving WT Bf-CM prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12575-022-00170-2.

Detecting endogenous TRIB2 protein expression by flow cytometry and Western blotting

Protein kinases catalyze the transfer of a phosphate group thereby activating proteins and initiating signaling cascades. Their cousins, the pseudokinases, are enzymatically nonactive counterparts of protein kinases that can be considered zombie enzymes. Interestingly, pseudokinases, which constitute about 10% of the human kinome, have been implicated in many cancers, despite their sequences predicting a lack of catalytic activity. Owing to recent research, it has been demonstrated that dysregulation of many pseudokinases triggers changes in cell signaling, proliferation, and drug resistance. This review is aimed at describing methods that can be used for detection of Tribbles family of pseudokinases, specifically TRIB2. We describe intracellular staining by flow cytometry and Western blotting techniques for the detection of endogenous TRIB2 protein.

Analysis of human Tribbles 2 (TRIB2) pseudokinase

Human Tribbles 2 (TRIB2) is a cancer-associated pseudokinase with a broad human protein interactome, including the well-studied AKT, C/EBPα and MAPK modules. Several lines of evidence indicate that human TRIB2 promotes cell survival and drug-resistance in solid tumors and blood cancers and is therefore of interest as a potential therapeutic target, although its physiological functions remain relatively poorly understood. The unique TRIB2 pseudokinase domain lacks the canonical 'DFG' motif, and subsequently possesses very low affinity for ATP in both the presence and absence of metal ions. However, TRIB2 also contains a unique cysteine-rich αC-helix, which interacts with a conserved peptide motif in its own carboxyl-terminal tail. This regulatory flanking region drives regulated interactions with distinct E3 ubiquitin ligases that serve to control the stability and turnover of TRIB2 client proteins. TRIB2 is also a low-affinity target of several known small-molecule protein kinase inhibitors, which were originally identified using purified recombinant TRIB2 proteins and a thermal shift assay. In this chapter, we discuss laboratory-based procedures for purification, stabilization and analysis of human TRIB2, including screening procedures that can be used for the identification of both reversible and covalent small molecule ligands.

TRIB2 regulates the expression of miR‑33a‑5p through the ERK/c‑Fos pathway to affect the imatinib resistance of chronic myeloid leukemia cells

Chronic myeloid leukemia (CML) is a hematological disease, and imatinib (IM) resistance represents a major problem for its clinical treatment. In the present study, the role of tribbles pseudokinase 2 (TRIB2) in IM resistance of CML and the possible mechanism were investigated. It was found that TRIB2 was highly expressed in IM-resistant patients with CML through the Oncomine database and this conclusion was confirmed using reverse transcription-quantitative PCR and western blot experiments. Knockdown of TRIB2 was found to increase the drug sensitivity of KG cells to IM using Cell-Counting Kit-8 (CCK-8) assays, and the low-expression TRIB2 mice were further found to be more sensitive to the IM and have a higher survival rate in leukemia model mice. Moreover, using western blot and luciferase experiments, it was found that TRIB2 could regulate c-Fos through the ERK signaling pathway, and c-Fos suppressed the transcriptional activity and the expression of miR-33a-5p. Further investigation identified that the binding site for c-Fos to function on miR-33a-5p was the -958-965 region. Finally, CCK-8 assays and western blot experiments demonstrated that miR-33a-5p could inhibit the proliferation of KG cells and reduce IM resistance by suppressing the expression of HMGA2. In conclusion, it was demonstrated that TRIB2 regulates miR-33a-5p to reverse IM resistance in CML, which may help identify novel targets and therapeutic strategies for the clinical treatment of IM resistance.

Tribbles 2 pseudokinase confers enzalutamide resistance in prostate cancer by promoting lineage plasticity

Enzalutamide, a second-generation antiandrogen, is commonly prescribed for the therapy of advanced prostate cancer, but enzalutamide-resistant, lethal, or incurable disease invariably develops. To understand the molecular mechanism(s) behind enzalutamide resistance, here, we comprehensively analyzed a range of prostate tumors and clinically relevant models by gene expression array, immunohistochemistry, and Western blot, which revealed that enzalutamide-resistant prostate cancer cells and tumors overexpress the pseudokinase, Tribbles 2 (TRIB2). Inhibition of TRIB2 decreases the viability of enzalutamide-resistant prostate cancer cells, suggesting a critical role of TRIB2 in these cells. Moreover, the overexpression of TRIB2 confers resistance in prostate cancer cells to clinically relevant doses of enzalutamide, and this resistance is lost upon inhibition of TRIB2. Interestingly, we found that TRIB2 downregulates the luminal markers androgen receptor and cytokeratin 8 in prostate cancer cells but upregulates the neuronal transcription factor BRN2 (Brain-2) and the stemness factor SOX2 (SRY-box 2) to induce neuroendocrine characteristics. Finally, we show that inhibition of either TRIB2 or its downstream targets, BRN2 or SOX2, resensitizes resistant prostate cancer cells to enzalutamide. Thus, TRIB2 emerges as a potential new regulator of transdifferentiation that confers enzalutamide resistance in prostate cancer cells via a mechanism involving increased cellular plasticity and lineage switching.

Comprehensive Profiling of Mammalian Tribbles Interactomes Implicates TRIB3 in Gene Repression

The three human Tribbles (TRIB) pseudokinases have been implicated in a plethora of signaling and metabolic processes linked to cancer initiation and progression and can potentially be used as biomarkers of disease and prognosis. While their modes of action reported so far center around protein-protein interactions, the comprehensive profiling of TRIB interactomes has not been reported yet. Here, we have developed a robust mass spectrometry (MS)-based proteomics approach to characterize Tribbles' interactomes and report a comprehensive assessment and comparison of the TRIB1, -2 and -3 interactomes, as well as domain-specific interactions for TRIB3. Interestingly, TRIB3, which is predominantly localized in the nucleus, interacts with multiple transcriptional regulators, including proteins involved in gene repression. Indeed, we found that TRIB3 repressed gene transcription when tethered to DNA in breast cancer cells. Taken together, our comprehensive proteomic assessment reveals previously unknown interacting partners and functions of Tribbles proteins that expand our understanding of this family of proteins. In addition, our findings show that MS-based proteomics provides a powerful tool to unravel novel pseudokinase biology.

Tribbles Gene Expression Profiles in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of death due to cancer in the world. Therefore, the identification of novel druggable targets is urgently needed. Tribbles proteins belong to a pseudokinase family, previously recognized in CRC as oncogenes and potential therapeutic targets. Here, we analyzed the expression of TRIB1, TRIB2, and TRIB3 simultaneously in 33 data sets from CRC based on available GEO profiles. We show that all three Tribbles genes are overrepresented in CRC cell lines and primary tumors, though depending on specific features of the CRC samples. Higher expression of TRIB2 in the tumor microenvironment and TRIB3 overexpression in an early stage of CRC development, unveil a potential and unexplored role for these proteins in the context of CRC. Differential Tribbles expression was also explored in diverse cellular experimental conditions where either genetic or pharmacological approaches were used, providing novel hints for future research. This comprehensive bioinformatic analysis provides new insights into Tribbles gene expression and transcript regulation in CRC.

Tribbles Gene Expression Profiles in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of death due to cancer in the world. Therefore, the identification of novel druggable targets is urgently needed. Tribbles proteins belong to a pseudokinase family, previously recognized in CRC as oncogenes and potential therapeutic targets. Here, we analyzed the expression of TRIB1, TRIB2, and TRIB3 simultaneously in 33 data sets from CRC based on available GEO profiles. We show that all three Tribbles genes are overrepresented in CRC cell lines and primary tumors, though depending on specific features of the CRC samples. Higher expression of TRIB2 in the tumor microenvironment and TRIB3 overexpression in an early stage of CRC development, unveil a potential and unexplored role for these proteins in the context of CRC. Differential Tribbles expression was also explored in diverse cellular experimental conditions where either genetic or pharmacological approaches were used, providing novel hints for future research. This comprehensive bioinformatic analysis provides new insights into Tribbles gene expression and transcript regulation in CRC.

RFWD2 Knockdown as a Blocker to Reverse the Oncogenic Role of TRIB2 in Lung Adenocarcinoma

RFWD2, an E3 ubiquitin ligase, is overexpressed in numerous human cancers, including leukemia, lung cancer, breast cancer, renal cell carcinoma, and colorectal cancer. The roles of RFWD2 in cancer are related to the targeting of its substrates for ubiquitination and degradation. This study aimed to investigate the role of TRIB2 in relation to the regulation of protein degradation through RFWD2. inBio Discover™ results demonstrated that TRIB2 can perform its functions by interacting with RFWD2 or other factors. TRIB2 can interact with and regulate RFWD2, which further attends the proteasome-mediated degradation of the RFWD2 substrate p-IκB-α. TRIB2 colocalizes with RFWD2-related IκB-α to form a ternary complex and further affects the IκB-α degradation by regulating its phosphorylation. Specific domain analysis showed that TRIB2 may bind to RFWD2 via its C-terminus, whereas it binds to IκB via its pseudokinase domain. TRIB2 acts as an oncogene and promotes cancer cell proliferation and migration, whereas RFWD2 knockdown reversed the role of TRIB2 in promoting cancer cell growth and colony formation in vitro and in vivo. In summary, this study reveals that TRIB2 promotes the progression of cancer by affecting the proteasome-mediated degradation of proteins through the interaction with RFWD2.

A methyltransferase-like 14/miR-99a-5p/tribble 2 positive feedback circuit promotes cancer stem cell persistence and radioresistance via histone deacetylase 2-mediated epigenetic modulation in esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a highly aggressive and treatment-resistant tumor. The biological implications and molecular mechanism of cancer stem-like cells (CSCs) in ESCC, which contribute to therapeutic resistance such as radioresistance, remain elusive.

METHODS

Quantitative real-time polymerase chain reaction, western blotting, immunohistochemistry, and in situ hybridization assays were used to detect methyltransferase-like 14 miR-99a-5p tribble 2 (METTL14/miR-99a-5p/TRIB2) expression in ESCC. The biological functions of METTL14/miR-99a-5p/TRIB2 were demonstrated in vitro and in vivo. Mass spectrum analysis was used to identify the downstream proteins regulated by TRIB2. Chromatin immunoprecipitation (IP), IP, N6 -methyladenosine (m6 A)-RNA IP, luciferase reporter, and ubiquitination assays were employed to explore the molecular mechanisms underlying this feedback circuit and its downstream pathways.

RESULTS

We found that miR-99a-5p was significantly decreased in ESCC. miR-99a-5p inhibited CSCs persistence and the radioresistance of ESCC cells, and miR-99a-5p downregulation predicted an unfavorable prognosis of ESCC patients. Mechanically, we unveiled a METTL14-miR-99a-5p-TRIB2 positive feedback loop that enhances CSC properties and radioresistance of ESCC cells. METTL14, an m6 A RNA methyltransferase downregulated in ESCC, suppresses TRIB2 expression via miR-99a-5p-mediated degradation of TRIB2 mRNA by targeting its 3' untranslated region, whereas TRIB2 induces ubiquitin-mediated proteasomal degradation of METTL14 in a COP1-dependent manner. METTL14 upregulates miR-99a-5p by modulating m6 A-mediated, DiGeorge critical region 8-dependent pri-mir-99a processing. Hyperactivation of TRIB2 resulting from this positive circuit was closely correlated with radioresistance and CSC characteristics. Furthermore, TRIB2 activates HDAC2 and subsequently induces p21 epigenetic repression through Akt/mTOR/S6K1 signaling pathway activation. Pharmacologic inhibition of HDAC2 effectively attenuates the TRIB2-mediated effect both in vitro and in patient-derived xenograft models.

CONCLUSION

Our data highlight the presence of the METTL14/miR-99a-5p/TRIB2 axis and show that it is positively associated with CSC characteristics and radioresistance of ESCC, suggesting potential therapeutic targets for ESCC treatment.

TRIB2 Stimulates Cancer Stem-Like Properties through Activating the AKT-GSK3β-β-Catenin Signaling Axis

Tribbles homolog 2 (TRIB2) is implicated in tumorigenesis and drug resistance in various types of cancers. However, the role of TRIB2 in the regulation of tumorigenesis and drug resistance of cancer stem cells (CSCs) is still elusive. In the present study, we showed increased expression of TRIB2 in spheroid-forming and aldehyde dehydrogenase-positive CSC populations of A2780 epithelial ovarian cancer cells. Short hairpin RNA-mediated silencing of TRIB2 expression attenuates the spheroid-forming, migratory, tumorigenic, and drug-resistant properties of A2780 cells, whereas overexpression of TRIB2 increases the CSC-like characteristics. TRIB2 overexpression induced GSK3β inactivation by augmenting AKT-dependent phosphorylation of GSK3β at Ser9, followed by increasing β-catenin level via reducing the GSK3β-mediated phosphorylation of β-catenin. Treatment of TRIB2-ovexpressed A2780 cells with the phosphoinositide-3-kinase inhibitor LY294002 abrogated TRIB2-stimulated proliferation, migration, drug resistance of A2780 cells. These results suggest a critical role for TRIB2 in the regulation of CSC-like properties by increasing the stability of β-catenin protein via the AKT-GSK3β-dependent pathways.

Functional annotation of noncoding mutations in cancer

Recurrent regulatory mutations affecting transcription factor binding sites in 2,500 cancer samples.

In a cancer genome, the noncoding sequence contains the vast majority of somatic mutations. While very few are expected to be cancer drivers, those affecting regulatory elements have the potential to have downstream effects on gene regulation that may contribute to cancer progression. To prioritize regulatory mutations, we screened somatic mutations in the Pan-Cancer Analysis of Whole Genomes cohort of 2,515 cancer genomes on individual bases to assess their potential regulatory roles in their respective cancer types. We found a highly significant enrichment of regulatory mutations associated with the deamination signature overlapping a CpG site in the CCAAT/Enhancer Binding Protein β recognition sites in many cancer types. Overall, 5,749 mutated regulatory elements were identified in 1,844 tumor samples from 39 cohorts containing 11,962 candidate regulatory mutations. Our analysis indicated 20 or more regulatory mutations in 5.5% of the samples, and an overall average of six per tumor. Several recurrent elements were identified, and major cancer-related pathways were significantly enriched for genes nearby the mutated regulatory elements. Our results provide a detailed view of the role of regulatory elements in cancer genomes.

Structure vs. Function of TRIB1-Myeloid Neoplasms and Beyond

The Tribbles family of proteins-comprising TRIB1, TRIB2, TRIB3 and more distantly related STK40-play important, but distinct, roles in differentiation, development and oncogenesis. Of the four Tribbles proteins, TRIB1 has been most well characterised structurally and plays roles in diverse cancer types. The most well-understood role of TRIB1 is in acute myeloid leukaemia, where it can regulate C/EBP transcription factors and kinase pathways. Structure-function studies have uncovered conformational switching of TRIB1 from an inactive to an active state when it binds to C/EBPα. This conformational switching is centred on the active site of TRIB1, which appears to be accessible to small-molecule inhibitors in spite of its inability to bind ATP. Beyond myeloid neoplasms, TRIB1 plays diverse roles in signalling pathways with well-established roles in tumour progression. Thus, TRIB1 can affect both development and chemoresistance in leukaemia; glioma; and breast, lung and prostate cancers. The pervasive roles of TRIB1 and other Tribbles proteins across breast, prostate, lung and other cancer types, combined with small-molecule susceptibility shown by mechanistic studies, suggests an exciting potential for Tribbles as direct targets of small molecules or biomarkers to predict treatment response.

Tribbles Pseudokinases in Colorectal Cancer

The Tribbles family of pseudokinases controls a wide number of processes during cancer on-set and progression. However, the exact contribution of each of the three family members is still to be defined. Their function appears to be context-dependent as they can act as oncogenes or tumor suppressor genes. They act as scaffolds modulating the activity of several signaling pathways involved in different cellular processes. In this review, we discuss the state-of-knowledge for TRIB1, TRIB2 and TRIB3 in the development and progression of colorectal cancer. We take a perspective look at the role of Tribbles proteins as potential biomarkers and therapeutic targets. Specifically, we chronologically systematized all available articles since 2003 until 2020, for which Tribbles were associated with colorectal cancer human samples or cell lines. Herein, we discuss: (1) Tribbles amplification and overexpression; (2) the clinical significance of Tribbles overexpression; (3) upstream Tribbles gene and protein expression regulation; (4) Tribbles pharmacological modulation; (5) genetic modulation of Tribbles; and (6) downstream mechanisms regulated by Tribbles; establishing a comprehensive timeline, essential to better consolidate the current knowledge of Tribbles' role in colorectal cancer.

The Critical Role of TRIB2 in Cancer and Therapy Resistance

Simple Summary

The Tribbles proteins are members of CAMK Ser/Thr protein kinase family. They are evolutionary conserved pseudokinases found in most tissues of eukaryotic organisms. This ubiquitously expressed protein family is characterized by containing a catalytically deficient kinase domain which lacks amino acid residues required for the productive interaction with ATP and metal ions. Tribbles proteins exert their biological functions mainly through direct interaction with MAPKK and AKT proteins, therefore regulating important pathways involved in cell proliferation, apoptosis and differentiation. Due to the role of MAPKK and AKT signalling in the context of cancer development, Tribbles proteins have been recently considered as biomarkers of cancer progression. Furthermore, as the atypical pseudokinase domain retains a binding platform for substrates, Tribbles targeting provides an attractive opportunity for drug development.

Abstract

The Tribbles pseudokinases family consists of TRIB1, TRIB2, TRIB3 and STK40 and, although evolutionarily conserved, they have distinctive characteristics. Tribbles members are expressed in a context and cell compartment-dependent manner. For example, TRIB1 and TRIB2 have potent oncogenic activities in vertebrate cells. Since the identification of Tribbles proteins as modulators of multiple signalling pathways, recent studies have linked their expression with several pathologies, including cancer. Tribbles proteins act as protein adaptors involved in the ubiquitin-proteasome degradation system, as they bridge the gap between substrates and E3 ligases. Between TRIB family members, TRIB2 is the most ancestral member of the family. TRIB2 is involved in protein homeostasis regulation of C/EBPα, β-catenin and TCF4. On the other hand, TRIB2 interacts with MAPKK, AKT and NFkB proteins, involved in cell survival, proliferation and immune response. Here, we review the characteristic features of TRIB2 structure and signalling and its role in many cancer subtypes with an emphasis on TRIB2 function in therapy resistance in melanoma, leukemia and glioblastoma. The strong evidence between TRIB2 expression and chemoresistance provides an attractive opportunity for targeting TRIB2.

Long noncoding RNA TUG1 regulates the progression of colorectal cancer through miR-542-3p/TRIB2 axis and Wnt/β-catenin pathway

BACKGROUND

Colorectal cancer (CRC) is one of the third normal malignancy worldwide. Taurine-upregulated gene 1 (TUG1), a member of long noncoding RNAs (lncRNAs), has been reported to be involved in various cancers. However, the mechanism underlying TUG1 in the progression of CRC remains unclear.

METHODS

The expression of TUG1, microRNA-542-3p (miR-542-3p), and tribbles homolog 2 (TRIB2) in CRC tissues and cells (LoVo and HCT116) were detected by quantitative real-time PCR (qRT-PCR). Methyl thiazolyl tetrazolium (MTT), transwell and flow cytometry assays were employed to evaluate the effects of TUG1 in CRC cells. The interaction between miR-542-3p and TUG1 or TRIB2 were verified by dual-luciferase reporter assay. A xenograft tumor model in nude mice was established to investigate the biological role of TUG1 in CRC in vivo.

RESULTS

TUG1 was increased in CRC tissues and cells (LoVo and HCT116) in contrast with adjacent normal tissues and normal intestinal mucous cells (CCC-HIE-2). Downregulation of TUG1 or TRIB2 suppressed the proliferation, migration, invasion, and induced apoptosis in CRC cells. And knockdown of TUG1 repressed tumor growth in vivo. Besides, overexpression of TRIB2 reversed the effects of TUG1 depletion on the progression of CRC. Meanwhile, TUG1 interacted with miR-542-3p and TRIB2 was a target of miR-542-3p. Furthermore, miR-542-3p knockdown or TRIB2 overexpression partly reversed the suppression effect of TUG1 depletion on the Wnt/β-catenin pathway.

CONCLUSIONS

TUG1 served as a tumor promoter, impeded the progression of CRC by miR-542-3p/TRIB2 axis to inactivate of Wnt/β-catenin pathway, which providing a novel target for CRC treatment.

Tribbles homolog 2 promotes hepatic fibrosis and hepatocarcinogenesis through phosphatase 1A-Mediated stabilization of yes-associated protein

BACKGROUND & AIMS

Hepatic stellate cells (HSCs) play critical roles in liver fibrosis and hepatocellular carcinoma (HCC). Tribbles homolog 2 (TRIB2) is an oncogene implicated in a variety of cancers, including liver cancer. However, the biological function and regulatory mechanism of TRIB2 in HSCs are poorly understood. In addition, little is known about its role in liver fibrosis progression to HCC. Here, we revealed the clinical significance of TRIB2 in liver fibrosis and HCC development.

METHODS

We investigated TRIB2 promoting liver fibrosis in vitro and in vivo. In mouse model of liver fibrosis and HCC, we measured hepatic fibrosis and HCC level through knockdown TRIB2 with shRNA. In addition, we performed western blotting, real-time quantitative PCR, immunofluorescence and co-immunoprecipitation assay to study TRIB2 function in LX-2 cells.

RESULTS

TRIB2 expression was strongly upregulated in human fibrotic liver tissues and HCC tissues. TRIB2 colocalized with α-smooth muscle actin (α-SMA) in fibrotic and HCC liver tissues. Knockdown of TRIB2 inhibited HSC activation and liver fibrosis in vitro and in vivo. TRIB2 promoted Yes-associated protein (YAP) stabilization, nuclear localization, and subsequent fibrotic gene expression independent of the MST-LATS phosphorylation cascade in HSCs. TRIB2 interacted with YAP to recruit phosphatase 1A (PP1A), promoting PP1A-mediated YAP dephosphorylation. TRIB2 knockdown potently attenuated the development of fibrosis-associated liver cancer.

CONCLUSIONS

TRIB2 is an attractive target for hepatic fibrosis and fibrosis-associated liver cancer treatment.

Upregulation of TRIB2 by Wnt/β-catenin activation in BRAFV600E papillary thyroid carcinoma cells confers resistance to BRAF inhibitor vemurafenib

PURPOSE

The BRAF^V600E mutation is an oncogenic driver associated with aggressive tumor behaviors and increased mortality among patients with papillary thyroid cancer (PTC). Although the BRAF inhibitor vemurafenib gave promising results in BRAF^V600E-mutant PTC, resistance development remains a major clinical challenge. This study aimed to explore the mechanisms underlying drug resistance in PTC.

METHODS

Two vemurafenib-resistant PTC cell lines (KTC1 and BCPAP) were established by continuous treatment with vemurafenib for 5 months. The knockdown and upregulation of Tribbles homolog 2 (TRIB2) in PTC cells were achieved by the transfection with short hairpin RNA against TRIB2 or recombinant lentiviral vector carrying TRIB2, respectively. The β-catenin inhibitor, ICG-001, was used for the inhibition of the Wnt/β-catenin signaling in PTC cells.

RESULTS

Vemurafenib-resistant PTC cells showed higher TRIB2 expression, upregulated ERK and AKT activation, enhanced invasive capacity, and increased epithelial-mesenchymal transition compared to the drug-sensitive groups. TRIB2 knockdown repressed the activation of ERK and AKT, inhibited invasion and EMT, and induced apoptosis of PTC cells. TRIB2 deficiency also enhanced the sensitivity of both PTC cells to vemurafenib. Vemurafenib-resistant PTC cells showed elevated expression of β-catenin in both cytoplasm and nucleus. The pre-incubation of cells with β-catenin inhibitor significantly inhibited TRIB2 expression, suppressed EMT, and repressed the activation of ERK and AKT in vemurafenib-resistant cells.

CONCLUSION

Our study showed that the upregulation of TRIB2 by the Wnt/β-catenin activation confers resistance to vemurafenib in PTC with BRAF^V600 mutation. These findings support the potential use of TRIB2 as a therapeutic target for resistant PTC.

The circadian rhythm and core gene Period2 regulate the chemotherapy effect and multidrug resistance of ovarian cancer through the PI3K signaling pathway

Background: Ovarian cancer is the most lethal cancer in the female reproductive system. It has been shown that ‘time chemotherapy’ of ovarian cancer has an important impact on the chemotherapy effect and prognosis of patients, but the specific mechanism is not known. Methods: We designed a case–control study in strict accordance with epidemiological principles. We collected resection samples of ovarian cancer patients who worked night-shifts and those who did not, and analyzed the differences in protein expression. Through construction of a normal/circadian-rhythm disorder model of ovarian cancer in nude mice, we explored the molecular mechanism of a ‘biological clock’ rhythm on treatment of ovarian cancer. Results: Expression of interleukin (IL)-6, programmed cell death receptor-1 (PD-1) and programmed death ligand 1 (PD-L1) increased, and expression of tumor necrosis factor (TNF)-α, Period 1 (Per1) and Period 2 (Per2) decreased in the night-shift group. Methylation of CpG islands in the promoter of Per2 could result in its decreased expression in SKOV3/DDP (Cisplatin) cells. Dysrhythmia of the circadian clock: (i) had a negative effect on the chemotherapy effect against ovarian cancer; (ii) affected expression of immune factors and the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signaling pathway. Conclusion: The Per2 gene can affect the drug resistance of ovarian cancer by inhibiting the PI3K/Akt signaling pathway and then acting on its downstream drug-resistance factors, thereby providing a new target for ovarian cancer treatment.

Tribbles homolog 2 (Trib2), a pseudo serine/threonine kinase in tumorigenesis and stem cell fate decisions

The family of Tribbles proteins play many critical nonenzymatic roles and regulate a wide range of key signaling pathways. Tribbles homolog 2 (Trib2) is a pseudo serine/threonine kinase that functions as a scaffold or adaptor in various physiological and pathological processes. Trib2 can interact with E3 ubiquitin ligases and control protein stability of downstream effectors. This protein is induced by mitogens and enhances the propagation of several cancer cells, including myeloid leukemia, liver, lung, skin, bone, brain, and pancreatic. Thus, Trib2 can be a predictive and valuable biomarker for the diagnosis and treatment of cancer. Recent studies have illustrated that Trib2 plays a major role in cell fate determination of stem cells. Stem cells have the capacity to self-renew and differentiate into specific cell types. Stem cells are important sources for cell-based regenerative medicine and drug screening. Trib2 has been found to increase the self-renewal ability of embryonic stem cells, the reprogramming efficiency of somatic cells, and chondrogenesis. In this review, we will focus on the recent advances of Trib2 function in tumorigenesis and stem cell fate decisions.

LncRNA XIST promotes the progression of laryngeal squamous cell carcinoma via sponging miR-125b-5p to modulate TRIB2

Objective: X inactivate-specific transcript (XIST) is an attractive long noncoding RNA (lncRNA) functioning as an indicator of various human tumors, including laryngeal squamous cell carcinoma (LSCC). The present study was conducted to explore a novel regulatory network of lncRNA XIST in LSCC cells.

Materials and methods: Quantitative real-time polymerase chain reaction (QRT-PCR) was used to detect the expression levels of XIST, miR-125b-5p and TRIB2 in LSCC cells and tissues. Cell proliferation, apoptosis, migration and invasion were detected by Cell Counting Kit-8 (CCK-8), flow cytometry and Transwell assays, separately. The relationship among XIST, miR-125b-5p and tribbles homolog 2 (TRIB2) was predicted by starBase v2.0 or TargetScan and confirmed by Dual-luciferase reporter assay. The TRIB2 protein expression was quantified by Western blot assay. Murine xenograft model was utilized to validate the role of XIST in vivo.

Results: XIST was notably up-regulated in LSCC tissues and cells, and the high level of XIST was associated with the low survival rate of LSCC patients. XIST knockdown markedly repressed cell proliferation, migration and invasion and promoted the apoptosis of LSCC cells and the effects were antagonized by loss of miR-125b-5p. MiR-125b-5p was a target of XIST in LSCC cells, and it could bind to TRIB2 as well. Moreover, XIST-loss-induced down-regulation of TRIB2 could be significantly reversed by miR-125b-5p knockdown. XIST promoted the growth of LSCC tumor in vivo.

Conclusion: LncRNA XIST promoted the malignance of LSCC cells partly through competitively binding to miR-125b-5p, which in turn increased TRIB2 expression.

One-minute and green synthesis of magnetic iron oxide nanoparticles assisted by design of experiments and high energy ultrasound: Application to biosensing and immunoprecipitation

The present study is focused on the ultrafast and green synthesis, via the co-precipitation method, of magnetic nanoparticles (MNPs) based on iron oxides using design of experiments (DOE) and high energy sonochemical approach, considering two main factors: amplitude (energy) of the ultrasound probe and sonication time. The combination of these techniques allowed the development of a novel one-minute green synthesis, which drastically reduced the amount of consumed energy, solvents, reagents, time and produced residues. This green sonochemical synthesis permitted to obtain mean particle sizes of 11 ± 2 nm under the optimized conditions of amplitude = 40% (2826 J) and time = 1 min. Their composition, structure, size, morphology and magnetic properties were assessed through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning and transmission electron microscopy (SEM & TEM), and vibrating sample magnetometry (VSM). The characterization results indicate the proper formation of MNPs, and the correct functionalization of MNPs with different coating agents. The functionalized MNPs were used as: i) biosensor, which could detect mercury in water in the range of 0.030-0.060 ppm, and ii) support onto which polyclonal antibodies were anchored and successfully bound to an osteosarcoma cell line expressing the target protein (TRIB2-GFP), as part of an immunoprecipitation assay.

Use of signals of positive and negative selection to distinguish cancer genes and passenger genes

A major goal of cancer genomics is to identify all genes that play critical roles in carcinogenesis. Most approaches focused on genes positively selected for mutations that drive carcinogenesis and neglected the role of negative selection. Some studies have actually concluded that negative selection has no role in cancer evolution. We have re-examined the role of negative selection in tumor evolution through the analysis of the patterns of somatic mutations affecting the coding sequences of human genes. Our analyses have confirmed that tumor suppressor genes are positively selected for inactivating mutations, oncogenes, however, were found to display signals of both negative selection for inactivating mutations and positive selection for activating mutations. Significantly, we have identified numerous human genes that show signs of strong negative selection during tumor evolution, suggesting that their functional integrity is essential for the growth and survival of tumor cells.

Trib1 regulates T cell differentiation during chronic infection by restraining the effector program

In chronic infections, the immune response fails to control virus, leading to persistent antigen stimulation and the progressive development of T cell exhaustion. T cell effector differentiation is poorly understood in the context of exhaustion, but targeting effector programs may provide new strategies for reinvigorating T cell function. We identified Tribbles pseudokinase 1 (Trib1) as a central regulator of antiviral T cell immunity, where loss of Trib1 led to a sustained enrichment of effector-like KLRG1⁺ T cells, enhanced function, and improved viral control. Single-cell profiling revealed that Trib1 restrains a population of KLRG1⁺ effector CD8 T cells that is transcriptionally distinct from exhausted cells. Mechanistically, we identified an interaction between Trib1 and the T cell receptor (TCR) signaling activator, MALT1, which disrupted MALT1 signaling complexes. These data identify Trib1 as a negative regulator of TCR signaling and downstream function, and reveal a link between Trib1 and effector versus exhausted T cell differentiation that can be targeted to improve antiviral immunity.

Harmine and Piperlongumine Revert TRIB2-Mediated Drug Resistance

Simple Summary

Poor survival and treatment failure of patients with cancer are mainly due to resistance to therapy. Tribbles homologue 2 (TRIB2) has recently been identified as a protein that promotes resistance to several anti-cancer drugs. In this study, RNA sequencing and bioinformatics analysis were used with the aim of characterizing the impact of TRIB2 on the expression of genes and developing pharmacological strategies to revert these TRIB2-mediated changes, thereby overcoming therapy resistance. We show that two naturally occurring alkaloids, harmine and piperlongumine, inverse the gene expression profile produced by TRIB2 and sensitize cancer cells to anti-cancer drugs. Our data suggest that harmine and piperlongumine or similar compounds might have the potential to overcome TRIB2-mediated therapy resistance in cancer patients.

Abstract

Therapy resistance is responsible for most relapses in patients with cancer and is the major challenge to improving the clinical outcome. The pseudokinase Tribbles homologue 2 (TRIB2) has been characterized as an important driver of resistance to several anti-cancer drugs, including the dual ATP-competitive PI3K and mTOR inhibitor dactolisib (BEZ235). TRIB2 promotes AKT activity, leading to the inactivation of FOXO transcription factors, which are known to mediate the cell response to antitumor drugs. To characterize the downstream events of TRIB2 activity, we analyzed the gene expression profiles of isogenic cell lines with different TRIB2 statuses by RNA sequencing. Using a connectivity map-based computational approach, we identified drug-induced gene-expression profiles that invert the TRIB2-associated expression profile. In particular, the natural alkaloids harmine and piperlongumine not only produced inverse gene expression profiles but also synergistically increased BEZ235-induced cell toxicity. Importantly, both agents promote FOXO nuclear translocation without interfering with the nuclear export machinery and induce the transcription of FOXO target genes. Our results highlight the great potential of this approach for drug repurposing and suggest that harmine and piperlongumine or similar compounds might be useful in the clinic to overcome TRIB2-mediated therapy resistance in cancer patients.

Synergetic therapy of glioma mediated by a dual delivery system loading α-mangostin and doxorubicin through cell cycle arrest and apoptotic pathways

Two of the biggest hurdles in the deployment of chemotherapeutics against glioma is a poor drug concentration at the tumor site and serious side effects to normal tissues. Nanocarriers delivering different drugs are considered to be one of the most promising alternatives. In this study, a dual delivery system (methoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL)) loaded with α-mangostin (α-m) and doxorubicin (Dox) was decorated and constructed by self-assembly to determine its ability to treat glioma. Molecular dynamics simulations showed that MPEG-PCL could provide ideal interaction positions for both α-m and Dox, indicating that the two drugs could be loaded into MPEG-PCL. Based on the in vitro results, MPEG-PCL loaded with α-m and Dox (α-m-Dox/M) with a size of 25.68 nm and a potential of -1.51 mV was demonstrated to significantly inhibit the growth and promote apoptosis in Gl261, C6 and U87 cells, and the effects of the combination were better than each compound alone. The mechanisms involved in the suppression of glioma cell growth were blockage of the cell cycle in S phase by inhibition of CDK2/cyclin E1 and promotion of apoptosis through the Bcl-2/Bax pathway. The synergetic effects of α-m-Dox/M effectively inhibited tumor growth and prolonged survival time without toxicity in mouse glioma models by inducing glioma apoptosis, inhibiting glioma proliferation and limiting tumor angiogenesis. In conclusion, a codelivery system was synthesized to deliver α-m and Dox to the glioma, thereby suppressing the development of glioma by the mechanisms of cell cycle arrest and cellular apoptosis, which demonstrated the potential of this system to improve the chemotherapy response of glioma.

Functional effects of Tribbles homolog 2 in bovine ovarian granulosa cells†

Tribbles homologs (TRIB) 1, 2, and 3 represent atypical members of the serine/threonine kinase superfamily. We previously identified TRIB2 as a differentially expressed gene in granulosa cells (GCs) of bovine preovulatory follicles. The current study aimed to further investigate TRIB2 regulation and study its function in the ovary. GCs were collected from follicles at different developmental stages: small antral follicles (SF), dominant follicles (DF) at day 5 of the estrous cycle, and hCG-induced ovulatory follicles (OFs). RT-qPCR analyses showed greater expression of TRIB2 in GC of DF as compared to OF and a significant downregulation of TRIB2 steady-state mRNA amounts by hCG/LH, starting at 6 h through 24 h post-hCG as compared to 0 h. Specific anti-TRIB2 polyclonal antibodies were generated and western blot analysis confirmed TRIB2 downregulation by hCG at the protein level. In vitro studies showed that FSH stimulates TRIB2 expression in GC. Inhibition of TRIB2 using CRISPR/Cas9 resulted in a significant increase in PCNA expression and an increase in steroidogenic enzyme CYP19A1 expression, while TRIB2 overexpression tended to decrease GC proliferation. TRIB2 inhibition also resulted in a decrease in transcription factors connective tissue growth factor (CTGF) and ankyrin repeat domain-containing protein 1 (ANKRD1) expression, while TRIB2 overexpression increased CTGF and ANKRD1. Additionally, western blot analyses showed reduction in ERK1/2 (MAPK3/1) and p38MAPK (MAPK14) phosphorylation levels following TRIB2 inhibition, while TRIB2 overexpression increased p-ERK1/2 and p-p38MAPK. These results provide evidence that TRIB2 modulates MAPK signaling in GC and that TRIB2 could act as a regulator of GC proliferation and function, which could affect steroidogenesis during follicular development.

PBX3 in Cancer

PBX3 is a homeodomain-containing transcription factor of the pre-B cell leukemia (PBX) family, members of which have extensive roles in early development and some adult processes. A number of features distinguish PBX3 from other PBX proteins, including the ability to form specific and stable interactions with DNA in the absence of cofactors. PBX3 has frequently been reported as having a role in the development and maintenance of a malignant phenotype, and high levels of PBX3 tumor expression have been linked to shorter overall survival in cancer. In this review we consider the similarities and differences in the function of PBX3 in different cancer types and draw together the core signaling pathways involved to help provide a better insight into its potential as a therapeutic target.

Prospects for pharmacological targeting of pseudokinases

Pseudokinases are members of the protein kinase superfamily but signal primarily through noncatalytic mechanisms. Many pseudokinases contribute to the pathologies of human diseases, yet they remain largely unexplored as drug targets owing to challenges associated with modulation of their biological functions. Our understanding of the structure and physiological roles of pseudokinases has improved substantially over the past decade, revealing intriguing similarities between pseudokinases and their catalytically active counterparts. Pseudokinases often adopt conformations that are analogous to those seen in catalytically active kinases and, in some cases, can also bind metal cations and/or nucleotides. Several clinically approved kinase inhibitors have been shown to influence the noncatalytic functions of active kinases, providing hope that similar properties in pseudokinases could be pharmacologically regulated. In this Review, we discuss known roles of pseudokinases in disease, their unique structural features and the progress that has been made towards developing pseudokinase-directed therapeutics.

Pseudokinases: a tribble-edged sword

Advances in the understanding of the Tribbles family of pseudokinases (TRIB1, TRIB2 and TRIB3) reveal these proteins as potentially valuable biomarkers of disease diagnosis, prognosis, prediction and clinical strategy. In their role as signalling mediators and scaffolding proteins, TRIBs lead to changes in protein stability and activity, which impact on diverse cellular processes such as proliferation, differentiation, cell cycle and cell death. We review the role of TRIB proteins as promising therapeutic targets, with an emphasis on their role in cancer, and as biomarkers, with potential application across diverse pathological processes.

Combined elevation of TRIB2 and MAP3K1 indicates poor prognosis and chemoresistance to temozolomide in glioblastoma

Introduction

Glioblastoma (GBM) is the most lethal primary malignant brain tumor in adults with poor survival due to acquired therapeutic resistance and rapid recurrence. Currently, the standard clinical strategy for glioma includes maximum surgical resection, radiotherapy, and temozolomide (TMZ) chemotherapy; however, the median survival of patients with GBM remains poor despite these comprehensive therapies. Therefore, the identification of new prognostic biomarkers is urgently needed to evaluate the malignancy and long‐term outcome of glioma.

Aims

To further investigate prognostic biomarkers and potential therapeutic targets for GBM.

Results

In this study, we identified tribbles pseudokinase 2 (TRIB2) as one of the genes that is most correlated with pathological classification, radioresistance, and TMZ resistance in glioma. Additionally, the expression of mitogen‐activated protein kinase kinase kinase 1 (MAP3K1) showed a strong correlation with TRIB2. Moreover, a combined increase in TRIB2 and MAP3K1 was observed in GBM and indicated a poor prognosis of patients with glioma. Finally, enriched TRIB2 expression and MAP3K1 expression were shown to be associated with resistance to TMZ and radiotherapy.

Conclusion

Combined elevation of TRIB2 and MAP3K1 could be novel prognostic biomarkers and potential therapeutic targets to evaluate the malignancy and long‐term outcomes of GBM.

Uncovering Potential Therapeutic Targets in Colorectal Cancer by Deciphering Mutational Status and Expression of Druggable Oncogenes

Background: Numerous driver mutations have been identified in colorectal cancer (CRC), but their relevance to the development of targeted therapies remains elusive. The secondary effects of pathogenic driver mutations on downstream signaling pathways offer a potential approach for the identification of therapeutic targets. We aimed to identify differentially expressed genes as potential drug targets linked to driver mutations. Methods: Somatic mutations and the gene expression data of 582 CRC patients were utilized, incorporating the mutational status of 39,916 and the expression levels of 20,500 genes. To uncover candidate targets, the expression levels of various genes in wild-type and mutant cases for the most frequent disruptive mutations were compared with a Mann–Whitney test. A survival analysis was performed in 2100 patients with transcriptomic gene expression data. Up-regulated genes associated with worse survival were filtered for potentially actionable targets. The most significant hits were validated in an independent set of 171 CRC patients. Results: Altogether, 426 disruptive mutation-associated upregulated genes were identified. Among these, 95 were linked to worse recurrence-free survival (RFS). Based on the druggability filter, 37 potentially actionable targets were revealed. We selected seven genes and validated their expression in 171 patient specimens. The best independently validated combinations were DUSP4 (p = 2.6 × 10⁻¹²) in ACVR2A mutated (7.7%) patients; BMP4 (p = 1.6 × 10⁻⁰⁴) in SOX9 mutated (8.1%) patients; TRIB2 (p = 1.35 × 10⁻¹⁴) in ACVR2A mutated patients; VSIG4 (p = 2.6 × 10⁻⁰⁵) in ANK3 mutated (7.6%) patients, and DUSP4 (p = 7.1 × 10⁻⁰⁴) in AMER1 mutated (8.2%) patients. Conclusions: The results uncovered potentially druggable genes in colorectal cancer. The identified mutations could enable future patient stratification for targeted therapy.

Ultrasensitive amplification-free detection of protein kinase based on catalyzed assembly and enumeration of gold nanoparticles

A single-particle enumeration method based on phosphorylation-directed in situ assembly of gold nanoparticles is developed for the ultrasensitive sensing of cellular protein kinase A activity. In comparison to existing strategies, the proposed new method demonstrates five orders of linear range and improves the detection limit up to 10-to-1000 fold without the involvement of target amplification.

miR-96 exerts carcinogenic effect by activating AKT/GSK-3β/β-catenin signaling pathway through targeting inhibition of FOXO1 in hepatocellular carcinoma

Background

The aim of this research was to investigate the mechanism of miR-96 affecting hepatocellular carcinoma (HCC).

Methods

mRNA and protein expression was detected by qRT-PCR and Western blot, respectively. HepG2 cells were transfected and grouped as follows: miR-NC group, miR-mimics group, NC + Vector group, mimics + Vector group, mimics + FOXO1 group. Luciferase reporter assay was performed. MTT and Transwell assay was conducted. In vivo studies by nude mice were performed. Immunohistochemistry and immunofluorescence was executed.

Results

Up-regulated miR-96 and down-regulated FOXO1 was found in tumor tissues and HepG2 cells (P < 0.01). FOXO1 was directly suppressed by miR-96. Compared with NC + Vector group, mimics + Vector group has higher OD495 value (P < 0.05), higher migration and invasion cells (P < 0.01), larger transplanted tumor volume (P < 0.01), lower FOXO1 positive cell numbers (P < 0.01), higher p-AKT and p-GSK-3β expression (P < 0.01), lower p-β-catenin expression (P < 0.01), more β-catenin expression in the nucleus (P < 0.01). Compared with mimics + Vector group, mimics + FOXO1 group has lower OD495 value (P < 0.05), lower migration and invasion cells (P < 0.01), smaller transplanted tumor volume (P < 0.01), higher FOXO1 positive cells (P < 0.01), lower p-AKT and p-GSK-3β expression (P < 0.01), higher p-β-catenin expression (P < 0.01), less β-catenin expression in the nucleus (P < 0.01).

Conclusion

miR-96 exerts carcinogenic effect by activating AKT/GSK-3β/β-catenin signaling pathway through targeting inhibition of FOXO1 in HCC.

Systems Biology Approach to Identify Novel Genomic Determinants for Pancreatic Cancer Pathogenesis

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with a 5-year survival rate of <8%. Its dismal prognosis stems from inefficient therapeutic modalities owing to the lack of understanding about pancreatic cancer pathogenesis. Considering the molecular complexity and heterogeneity of PDAC, identification of novel molecular contributors involved in PDAC onset and progression using global "omics" analysis will pave the way to improved strategies for disease prevention and therapeutic targeting. Meta-analysis of multiple miRNA microarray datasets containing healthy controls (HC), chronic pancreatitis (CP) and PDAC cases, identified 13 miRNAs involved in the progression of PDAC. These miRNAs showed dysregulation in both tissue as well as blood samples, along with progressive decrease in expression from HC to CP to PDAC. Gene-miRNA interaction analysis further elucidated 5 miRNAs (29a/b, 27a, 130b and 148a) that are significantly downregulated in conjunction with concomitant upregulation of their target genes throughout PDAC progression. Among these, miRNA-29a/b targeted genes were found to be most significantly altered in comparative profiling of HC, CP and PDAC, indicating its involvement in malignant evolution. Further, pathway analysis suggested direct involvement of miRNA-29a/b in downregulating the key pathways associated with PDAC development and metastasis including focal adhesion signaling and extracellular matrix organization. Our systems biology data analysis, in combination with real-time PCR validation indicates direct functional involvement of miRNA-29a in PDAC progression and is a potential prognostic marker and therapeutic candidate for patients with progressive disease.

The cell biology behind the oncogenic PIP3 lipids

The different mechanisms of phosphoinositide 3-kinase (PI3K) activation in cancer as well as the events that result in PI3K pathway reactivation after patient treatment with PI3K inhibitors was discussed on October 15-17th, 2018, in the medieval town of Baeza (Universidad Internacional de Andalucía, Spain) at the workshop entitled 'The cell biology behind the oncogenic PIP3 lipids'. These topics and the data presented regarding cellular functions altered by PI3K deregulation, the cooperation of PI3K/PTEN mutations with other tumor drivers, and the lessons learned for PI3K-targeted therapy, are discussed below.

TRIB2 functions as novel oncogene in colorectal cancer by blocking cellular senescence through AP4/p21 signaling

Background

Cellular senescence is a state of irreversible cell growth arrest and senescence cells permanently lose proliferation potential. Induction of cellular senescence might be a novel therapy for cancer cells. TRIB2 has been reported to participate in regulating proliferation and drug resistance of various cancer cells. However, the role of TRIB2 in cellular senescence of colorectal cancer (CRC) and its molecular mechanism remains unclear.

Methods

The expression of TRIB2 in colorectal cancer tissues and adjacent tissues was detected by immunohistochemistry and RT-PCR. The growth, cell cycle distribution and cellular senescence of colorectal cancer cells were evaluated by Cell Counting Kit-8 (CCK8) assay, flow cytometry detection and senescence-associated β-galactosidase staining, respectively. Western blot, RT-PCR and luciferase assay were performed to determine how TRIB2 regulates p21. Immunoprecipitation (IP) and chromatin-immunoprecipitation (ChIP) were used to investigate the molecular mechanisms.

Results

We found that TRIB2 expression was elevated in CRC tissues compared to normal adjacent tissues and high TRIB2 expression indicated poor prognosis of CRC patients. Functionally, depletion of TRIB2 inhibited cancer cells proliferation, induced cell cycle arrest and promoted cellular senescence, whereas overexpression of TRIB2 accelerated cell growth, cell cycle progression and blocked cellular senescence. Further studies showed that TRIB2 physically interacted with AP4 and inhibited p21 expression through enhancing transcription activities of AP4. The rescue experiments indicated that silencing of AP4 abrogated the inhibition of cellular senescence induced by TRIB2 overexpression.

Conclusion

These data demonstrate that TRIB2 suppresses cellular senescence through interaction with AP4 to down-regulate p21 expression. Therefore, TRIB2 could be a potential target for CRC treatment.

Electronic supplementary material

The online version of this article (10.1186/s12943-018-0922-x) contains supplementary material, which is available to authorized users.

T-ALL leukemia stem cell 'stemness' is epigenetically controlled by the master regulator SPI1

Leukemia stem cells (LSCs) are regarded as the origins and key therapeutic targets of leukemia, but limited knowledge is available on the key determinants of LSC 'stemness'. Using single-cell RNA-seq analysis, we identify a master regulator, SPI1, the LSC-specific expression of which determines the molecular signature and activity of LSCs in the murine Pten-null T-ALL model. Although initiated by PTEN-controlled β-catenin activation, Spi1 expression and LSC 'stemness' are maintained by a β-catenin-SPI1-HAVCR2 regulatory circuit independent of the leukemogenic driver mutation. Perturbing any component of this circuit either genetically or pharmacologically can prevent LSC formation or eliminate existing LSCs. LSCs lose their 'stemness' when Spi1 expression is silenced by DNA methylation, but Spi1 expression can be reactivated by 5-AZ treatment. Importantly, similar regulatory mechanisms may be also present in human T-ALL.